JACKSON TWP — Two huge trucks en route to a Marcellus Shale gas processing plant Thursday afternoon blocked the two main routes used to exit the Seneca Valley School District’s secondary campus, causing delays of about 20 minutes for dismissal. One of those trucks held up traffic on Hartmann Road in Jackson Township while another truck traveled down Little Creek Road, according to director of communications Linda Andreassi. Both of those are the two main roads used by Seneca Valley busses for dismissal. According to Andreassi, Jackson Township police forced the truck on Little Creek Road to pull over and wait until dismissal was over at the district. Police also regulated a nearby traffic light to ensure that traffic kept moving. However, school officials also were worried Thursday afternoon that the trucks could cause residual delays. That’s because all of the buses must pick up elementary students after finishing their routes from the secondary campus, which were delayed because of the trucks. “When you have 4,000 people trying to exit the secondary campus, it creates a gridlock,” Andreassi said about the trucks.